DBCC CHECKDB requires some amount of temporary space, to find the amount of space required in advance using ESTIMATEONLY option it will estimate amount of space required.

Example:
SET NOCOUNT ON
DBCC CHECKDB (‘AdventureWorks’) WITH ESTIMATEONLY
GO

Estimated TEMPDB space needed for CHECKALLOC (KB)
————————————————-
70

Estimated TEMPDB space needed for CHECKTABLES (KB)
————————————————–
198468

DBCC execution completed. If DBCC printed error messages, contact your system administrator.